This invention relates generally to mail handling systems, and, more particularly to a system for reorienting a moving stream of generally flat articles.
In the field of automated mail processing, there are numerous inventions and machines designed to handle uniformly dimensioned articles, typically known as first class mail, ranging in size from post cards to business letter envelopes. There are, however, a limited number of machines designed to automate the processing of larger flat articles otherwise known as xe2x80x9cmail flats,xe2x80x9d which may be up to fifteen inches square and one and a quarter inches thick.
Current practices in automated mail handling include the placement of batches of flat mail, or mail flats, into feeders, which separate the individual pieces and expel those pieces in a serial stream having a vertical orientation and a predetermined periodicity or pitch between the leading edges of adjacent pieces. The mail flats in this vertically oriented stream are then reoriented and placed on a horizontal conveyor with another predetermined periodicity, for the purpose of further handling and processing. This reorientation process can be particularly challenging for several reasons.
One challenge to the reorientation process is the handling of magazines and newspapers. Magazines must be automatically handled by their bound edge, and newspapers must be handled along their final fold. This requirement is critical to achieving any sort of speed in the automatic handling process. For this reason, these articles are placed in the feeder bin with the bound edge or final fold facing downward and are expelled from the feeder in this orientation. Later, when magazines and newspapers are placed on the horizontal conveyor, they must have their bound edge or final fold facing forward for proper handling. Therefore, the reorientation step must be performed so that the bottom edge of the vertically oriented mail flats becomes the leading edge of the horizontally oriented mail flats.
Space constraints are another challenge in the reorientation process. Input feeders typically have maximum height, ergonomic limitations to allow an operator to conveniently and safely place stacks of mail into the feeder. The horizontal output conveyors typically have minimum height requirements for receiving the mail flats because of similar constraints in removing objects. Therefore, the reorientation apparatus is limited in the amount of height that it can use for the reorientation process. The height restriction is further aggravated by the size and nature of the mail flats to be handled. As mentioned, such mail flats may be up to 15 inches by 15 inches, with thicknesses up to 1xc2xc inches. Automatically reorienting a stiff 15xc3x9715xc3x971.25 inch parcel is much more challenging than reorienting a flexible magazine.
Mail processing machinery also needs to operate at a sufficient throughput, commonly measured as xe2x80x9cpieces per hourxe2x80x9d (pph), that is economically viable for the mail handling agency to sacrifice the electrical power and space requirements as well as justify the capital expenditure. The machinery must also have sufficient throughput and accuracy to justify replacement of manual labor.
A common method of handling mail is from a horizontally oriented conveyor. The horizontal conveyor affords the easiest means for handling mail flats. Also, various other devices, such as scanners, cameras and sorters, have already been designed to work with such conveyors. A key hurdle in designing systems is how to achieve high throughput without adjacent pieces colliding with each other. U.S. Pat. No. 5,860,504 discloses machinery that places mail flats on a horizontal conveyor using multiple input feeders, which individually sense openings on the horizontal conveyors and then deliver their individual pieces to the sensed openings. The mail flats being handled have already been reoriented for proper placement on the horizontal conveyor.
In one form, the present invention provides a system for reorienting flat articles in a serial input stream, including an input pocket located to receive a horizontally moving stream of substantially vertically oriented flat articles, a sensor located to sense the reception of each flat article in the input pocket, a drivable element located to engage each flat article in response to its sensed reception, a drive mechanism connected to the drivable element and adapted to controllably accelerate engaged flat articles substantially downwardly, and an effective curved path channel located to receive flat articles moved substantially downwardly from the drivable element and shaped to convey such received flat articles toward a substantially horizontal orientation.
In one refinement of the above embodiment, the input pocket includes an inclined element located to impart rotational movement to each flat article entering the input pocket using the horizontal movement thereof, and the input pocket includes an inclined member located to receive each flat article and stop rotational movement thereof
In another refinement of the above embodiment, each input pocket includes a trap door located for supporting a bottom edge of each flat article received in the input pocket, and also includes an actuator adapted for opening the trap door to allow downward movement of flat articles from the drop pocket. In a further refinement, the drivable element includes an engagement mechanism adapted to cause engagement of the flat articles by the drivable element.
In a still further refinement, a control system is included and coupled to the sensor, the trap door actuator, the engagement mechanism and the drivable element. The control system is adapted to respond to the sensed reception of flat articles in the drop pocket to activate the engagement mechanism to engage flat articles, to activate the trap door actuator to open the trap door and to activate the drive mechanism to accelerate engaged flat articles.
In yet a separate refinement, the effective curved path channel includes a driven conveyor located to engage flat articles and having a lower, flexible belt conveyor located to support flat articles along the entire length of the effective curved path channel and an upper, flexible belt conveyor adapted to place force on the lower, flexible belt conveyor and flat articles located thereon.
In another form of the present invention, a system for conveying flat articles from a substantially vertically oriented position to a substantially horizontally oriented position includes an effective curved path channel having a substantially vertically oriented input port and a substantially horizontally oriented output port, a lower, driven flexible belt conveyor located to form a lower boundary of the effective curved path channel from the input port to the output port, and an upper, driven flexible belt conveyor located to place force on a portion of the lower, flexible belt conveyor and any flat articles located between the lower, flexible belt conveyor and the upper, driven flexible belt conveyor.
In a refined version of this embodiment, the upper, flexible belt conveyor includes a supported driven axle, at least one free axle supported from and kept parallel to the driven axle, the free axle having a location which is angularly movable with respect to the driven axle, and at least one flexible belt engaged by the driven and free axles, wherein the free axle is adapted to place the force on the lower, flexible belt conveyor and any flat articles located between the lower, flexible belt conveyor and the free axle.
The method of the present invention covers reorienting flat articles in a serial input stream, including the steps of receiving a horizontally moving, serial input stream of substantially vertically oriented flat articles, sensing reception of each flat article, engaging each sensed flat article, accelerating each engaged flat article into substantially downward movement, and conveying each flat article with the substantial downward movement into a substantially horizontal orientation and movement.
In a refinement of this method, the step of receiving includes partially rotating each flat article towards the substantially horizontal orientation. In a further refinement, the step of receiving the input stream of flat articles includes supporting a bottom edge of each flat article with a trap door, and the step of accelerating the engaged flat article includes opening the trap door.